Why 1967-1975 well I consider it to be the ultimate period of the heaviest music recorded ever in history. 

Many of you consider Black Sabbath to be the heaviest of that period along with Uriah heep and Budgie, course also Hendrix and Cream and the who along with the more harder 60´s movement such as The kinks and Pretty Things for an example. 

Budgie Live at Sweden rock festival 1999

None of the bands received superstatus just a big cult following but there was a lot of bands who received a enourmous response in terms of fanadulation and great critical acclaim such as Captain Beyond, Straydog, Jericho and Swedens greatest band of that time November.

In Europe of that time the circuit was really big it also involved with the blues scene where a lot of bands were mixing blues with heavy riffs bands of that example is Killing Floor, 

Leslie West, Mountain Karlshamn 1998

Clark Hutchinson just to name a few. In America Grand Funk railroad and Mountain had opened doors for upcoming bands like Bang, Josefus, Poobah  just to mention a few of the these great acts.. 

A lot of rockfans today call bands like Rush and Dream Theatre the most progressive bands in the world well they are both great, but also in this period a lot of bands were experimenting with different styles of music mixing Jazz and Blues with heavy riffs bands to mention is Twenty sixtysix and then, Fusion Orchestra, Kin Ping Meh.

One thing combined all the great bands together they were still behind the major bands in forms of popularity and recordsales, anyhow in 1970-71 with the success of Black Sabbaths first album, other continents began to pop up bands, in Australia where Buffalo, Fanny Adams etc started to catch up with the european influences also Asia started to take notice with bands like Flower travelin band, Blues creation for example were soon following the european style, Deep Purple was pretty much a inspiration  as well as Sabbath in the involvement in the scene, Led Zeppelin wasnt as dominant as the other 2 bands but they had a impact.

Blue Oyster Cult Karlshamn 1998

While the circuit was going strongly in Europe and America the Swedish scene was starting to catch up in some ways November being number 1 band but some bands followed like Tungt Vatten, Life ,Alexander Lucas just to name a few but the Swedish scene was just going really strong in a couple of years until the bands started to play more soft, in Norway and Denmark there were bands too like Flax, Aunt Mary , Höst , Culpepers Orchard, System just to name a few that kept the scene alive. 

By 1975 bands like Genesis and Yes had reached peoples attention, they inspired a new scene to mix in other kinds of music, more complicated not simple riffs as previously but the heavyrock scene was still alive but in important countries like Germany the krautrock was taking over the scene of Floating rock as we call it and the scene in central europe was dying off while in England it kept going as well in America but a lot of bands that had played really heavy up to this point started to become softer, too bad I would say also the bigger bands had lost some of its fire from the beginning. 

Frank Marino & Mahogany Rush Sweden rock fest 2000

Some bands survived the change others dissapeared. Today there is a lot of great items from this great period . To end this article I would like to pont out my 10 favourite records for you of this period and there is much more to tell about the scene but I reckon this brief history will do. 

Here is my topten:

Captain Beyond Same

Jericho Same 

November En ny tid är här 

Leafhound Same 

Grand Theft Scream/It´s eating me alive 

Bang Same 

Buffalo Dead Forever 

Message From books and Dreams 

Incredible Hog Same 

Poobah Let me in 

its so much more but these are milestones in heavy brutal early seventies hardrock. For those who are new to these bands check them out and get them if you the find the records they are rare and expensive but they are worth it.